Jimro, I know there's powders out there that shoot bullets out extra fast and I didn't think of that. Most of 'em are ball powders. I don't know of any ball powder that shoots match bullets more accurate than extruded powder. And I don't think any powder slower than Varget should be used with 155's or 168's if best accuracy's the objective; their pressure curves are typically not all that consistant and repeatable.

HiBC, it's been my experience (and that of many others) that Sierra's 155's will shoot very accurate out of any barrel whose groove diameter is at least .0004" smaller than their .3084" diameter (at least all the one's are that I've measured) and have uniform dimensions for diameters and twist. Of course the barrel must be properly chambered and fit to a decent receiver that's properly affixed to the stock, too. I don't think a difference in BC has anything to do with accuracy. While a gas port costs velocity, the difference between a ported and unported barrel is insignificant. And it has nothing to do with accuracy. There's a greater spread in velocity across several people shooting the same rifle-ammo combination than between a ported and unported barrel both with the exact chamber, bore and groove dimensions shot by one person. And if Sierra's match bullets won't shoot as well as their owner expects, it's not the bullet's fault.